package com.lagou.edu.factory;

import com.lagou.edu.annotation.Autowired;
import com.lagou.edu.annotation.Service;
import com.lagou.edu.annotation.Transactional;
import com.lagou.edu.pojo.Account;
import com.lagou.edu.utils.TransactionManager;
import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;

import java.lang.annotation.Annotation;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Arrays;

/**
 * @author 应癫
 * <p>
 * <p>
 * 代理对象工厂：生成代理对象的
 */

@Service("proxyFactory")
public class ProxyFactory {

    @Autowired
    private TransactionManager transactionManager;

    /**
     * Jdk动态代理
     *
     * @param obj 委托对象
     * @return 代理对象
     */
    public Object getJdkProxy(Object obj) {

        // 获取代理对象
        return Proxy.newProxyInstance(obj.getClass().getClassLoader(), obj.getClass().getInterfaces(),
                new InvocationHandler() {
                    @Override
                    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                        Object result = null;

                        Boolean transactional = findAnnotationFromProxy(Transactional.class, proxy, method);
//                        Boolean transactional = method.isAnnotationPresent(Transactional.class);

                        try {
                            if (transactional) {
                                // 开启事务(关闭事务的自动提交)
                                transactionManager.beginTransaction();
                            }

                            result = method.invoke(obj, args);
                            if (transactional) {
                                // 提交事务
                                transactionManager.commit();

                            }
                        } catch (Exception e) {
                            e.printStackTrace();
                            if (transactional) {
                                // 回滚事务
                                transactionManager.rollback();
                            }
                            // 抛出异常便于上层servlet捕获
                            throw e;

                        }

                        return result;
                    }
                });

    }


    /**
     * 使用cglib动态代理生成代理对象
     *
     * @param obj 委托对象
     * @return
     */
    public Object getCglibProxy(Object obj) {
        return Enhancer.create(obj.getClass(), new MethodInterceptor() {
            @Override
            public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
                Object result = null;
                Boolean transactional = method.isAnnotationPresent(Transactional.class);
                try {
                    if (transactional) {
                        // 开启事务(关闭事务的自动提交)
                        transactionManager.beginTransaction();
                    }

                    result = method.invoke(obj, objects);
                    if (transactional) {
                        // 提交事务
                        transactionManager.commit();
                    }

                } catch (Exception e) {
                    e.printStackTrace();
                    if (transactional) {
                        // 回滚事务
                        transactionManager.rollback();
                    }
                    // 抛出异常便于上层servlet捕获
                    throw e;

                }
                return result;
            }
        });
    }

    public static boolean findAnnotationFromProxy(Class<? extends Annotation> cusAnnotation, Object target, Method method) throws NoSuchMethodException {

        Method targetMethod = target.getClass().getMethod(method.getName(), method.getParameterTypes());
        return method.isAnnotationPresent(cusAnnotation) || method.getDeclaringClass().isAnnotationPresent(cusAnnotation)
                || target.getClass().isAnnotationPresent(cusAnnotation) || targetMethod.isAnnotationPresent(cusAnnotation);
    }
}
